Similar problem has been detected:
I did a successful update, rebooted and then checked to make sure there were no further updates available. There were none so I quit the application and got an error message to say it had crashed.
reporter: libreport-2.9.3
cmdline: python3 /usr/bin/dnfdragora-updater
crash_function: _handle_dbus_error
exception_type: dnfdaemon.client.DaemonError
executable: /usr/bin/dnfdragora-updater
kernel: 4.15.3-300.fc27.x86_64
package: dnfdragora-updater-1.0.1-9.git20180108.b0e8a66.fc27
reason: __init__.py:250:_handle_dbus_error:dnfdaemon.client.DaemonError: g-dbus-error-quark: GDBus.Error:org.freedesktop.DBus.Error.NoReply: Message recipient disconnected from message bus without replying (4)
runlevel: N 5
type: Python3
uid: 1000